SU371209A1 - METHOD OF OBTAINING 2-CYANOCYCLOGEXANDION-1,3 - Google Patents

Description

one

This invention relates to the field of producing 2-cyanocyclohexanediones-1,3, which can be used in the synthesis of physiologically active substances, in particular steroids, alkaloids, as well as in the synthesis of various heterocyclic compounds.

A known method for the preparation of a-cyanocyclohexanones is that a-formylcyclohexanones are reacted with hydroxylamine, followed by treatment of the intermediate tetragndrobenzyloxazoles with strong bases.

The product yield is low. In this way, only monoketones can be obtained.

The proposed method is based on a known reaction, but makes it possible to obtain previously not described 2-cyanocyclohexanedione-1,3 with a fairly high yield.

The method for preparing 2-cyanocyclohexanediones-1, 3 is that 2-phenylaminomethylene cyclohexanedione-1, 3 is reacted with hydroxylamine, preferably taken in a 1.5-2 fold molar excess, followed by treatment of the intermediate 2-oximeminomethyl cyclohexanedione 1, 3 base or acid or by heating to - 140 ° C, and the selection of the target product by known methods.

Example 1. Obtaining 2-cyanocyclohexanedione-1, 3.

A solution of 7 g (32.6 psol) of 2-phenylaminomethylene cyclohexanedione-1, 3 and 1.6 g (49 mmol) of hydroxylamine in 0.8 l of ether is left at room temperature for a week, then the precipitated crystalline precipitate is filtered, washed with ether and crystallized from tetrahydrofuran. Get 2.2 g (50%) of the nitrile in the form of colorless plates with so pl. 208.5-210 ° C (vozg.).

Found,%: C 61.09; H 5.16; No. 10.05.

Sgntmog

Calculated 7o: C 61.31; H 5.15; N 10.21. IR (Y, slg): 1590, 1635, 1660, 2240, 2800-3200 (KBG).

Example 2. Obtaining 2-cyano-5,5-dimethylcyclohexanedione-1, 3.

A solution of 5 g (21 mmol) of 5,5-dimethyl-2-phenylaminomethylene cyclohexanedione-1, 3 and 2.9 g (42 mmol) of HzNOH-HCl in 120 ml of methanol is neutralized with an equivalent amount of 10% NaOH and left at room temperature for three days. Then the reaction mixture was sequentially concentrated in vacuo to 1/4 of the initial volume, diluted with 100 ml of water, extracted with ether, acidified with 15% HCl to pH 1-2, and extracted with chloroform. As a result of the usual treatment of the chloroform extract and crystallization of the product from tetrahydrofuran, 3.12 g (83%) of 5,5-dimethyl-2-hydroxyaminome 3 are obtained.

tilencykohexanedione-1,3 in the form of colorless plates with t. pl. 134-135 ° C (decomp.).

Found,%: C 58.89; H 7.23; N 7.49.

SenPMOz.

Calculated,% C 59.00; H 7.15; N 7.65.

IR (Y, CHi-i): 1570, 1650, 3120-3220 (KBr).

The specified oxyamine in an amount of 3.1 g is heated under vacuum of a water jet pump at a bath temperature of 140 ° C for 1-2 minutes, necessary for solidification of the initially formed melt, then rapidly cooled and the residue is crystallized from tetrahydrofuran. 2.5 g (90%) of 2-cyano5, 5-dimethylcyclohexanedione-1,3 are obtained in the form of colorless prisms with m.p. 220-222 ° (vozg.).

Found,%: C 65.13; H 6.86; N 8.52.

SENPKOG.

Calculated,%: C 65.44; H 6.71; N 8.48.

IR spectrum (Y, hedgehog); 1590, 1653, 2235, 2800-3200 (KBG).

Example 3. Obtaining 2-cyano-5-phenylcyclohexanedione-1, 3.

A solution of 1 g (3.44 mmol) of 5-phenyl-2-phenylaminomethylene cyclohexanedione-1, 3 and 480 mg (6.9 mmol) H2NOH; HCl in 60 ml of methanol is neutralized with an equivalent amount of 10% NaOH and left at room temperature for three days. Then the reaction mixture is successively evaporated twice in vacuo, diluted with 50 ml of water, extraction4

ether is added with ether, acidified with 15% HC1 to pH 1-2, and extracted with chloroform. The resulting conventional treatment of the chloroform extract (0.7 g) is dissolved in 20 ml of benzene and heated with a Dean-Stark apparatus in the presence of a catalytic amount of l-toluenesulfonic acid until the separation of water stops. After removal of benzene and crystallization of the product from tetrahydrofuran, 360 mg (50% calculated on the starting anilide) of 2-cyano-5-phenylcyclohexanedione-1, 3 are obtained in the form of colorless plates with mp. 221-222 ° C (vozg.).

Found,%: C 73.03; H 5.15; N 6.51. CiaHuNOa.

Calculated,%: C 73.22; H 5.20; N 6.57.

IR (Y, slg): 1540, 1620, 1655, 2229, 2800-3200 (KBG).

PREDIMET and 3 obretev in

Claims (2)

1. A method for preparing 2-dianocyclohexanedio-1, 1, 3, characterized in that 2-phenylaminomethylene cyclohexanedione-1, 3 is subjected to interaction with hydroxylamine, the resulting 2-hydroxyminomethyl cyclohexanedione-1, 3 is treated with a base or acid or heated to 140 ° C, and the desired product is isolated by known techniques. 2. A method according to claim I, wherein the hydroxylamines are taken in a 1.5-2 fold molar excess.